Want to keep mice away and onions fresh for months? Grab some old pantyhose, and drop a whole onion into the leg and tie a knot. Repeat with more onions until you fill both legs. Tie a large knot at top, and hang the hose somewhere dark and cool, like under the basement stairs. Just snip the onion free with scissors when you need it. The individually ventilated onions will stay fresh for months, and it is a natural rodent deterrent. Mice and other rodents do not like the smell of onions and will steer clear.